Method and apparatus for forming plastic explosives into strings



April 29, 1930. A. E. ANDELIN 1,755,328

METHOD AND APPARATUS FOR FORMING PLASTIC EXPLOSIVES INTO- STRINGS Filed Dec. 1, 1928 2 Sheets-Sheet l I I mu M ww w April 29, 1930. A. E. ANDELIN 1, 5

METHOD AND APPARATUS FOR FORMING PLASTIC EXPLOSIVES' INTO STRINGS Filed Dec. 1, 1928 2 Sheets-Sheet 2 S24, mfg \\1\ I {/26 I: 31.

Patented Apr. 29, '1930 PATENT OFFICE UNITED srarlszs ANTON ERIK AND ELIN, OF BROMARF, BJORKNAS, EINLAND ASSIGNOR TO FINSKLA FORCIT-DYNAMIT AKTIEBOLAGET, 0F HANGO, -IEINLAN1), A CORPORATION OF FINLAND METHOD AND APPARATUS FOR FORMING PLASTIC EXPLOSIVES INTO STRINGS Application filed December 1, 1928, Serial No. 323,985, and in Sweden October 31, 1927.

, lrVhen, forining plastio explosives into strings, for instance in the manufacture of dynamite cartridges, it has'hitherto been usual to press out the plastic explosive 5 through nozzles having a cross section suitable for the purpose.

According to the present invention the plastic explosive is formed into strings by passing it between rollers which around their 10 surfaces are provided with grooves, the form of which is so chosen as to give the strings formed when the plastic explosive passes between the rollers, the desired cross section;

In order to clearly explain the invention there is diagrammaticallyshown in the accompanying drawings by way of example, a form of construction of an apparatus suitable for the purpose.

Figure 1 shows a vertical section ofthe apparatus.

Figure 2 shows the apparatus from above.

Figure 3 shows a vertical III III in Figures 2 and 4. v

Figure 4 shows a vertical section on line IVIV in Figures 2 and 3.

Figure 5 shows a vertical section on line V'-V in Figures 2 and 3. t

Figure .6 shows avertical section on line VIVI in Figures 2 and 3.

Figure 7 shows a verticalsection on line VIL-VII in Figure 2.

Figure 8 shows on a larger scale a part of the grooves in the rollers shown in Figure 6.

1 is a table or board on which the plastic explosive to be formed into strings is fed seen inplan section on line to two ro1lers'2 and 3 arranged one above the other which rollers are rotatably mounted in frames 4, 19 between which rollers the explosive is pressed out into cake-like form or such like of suitable thickness determined by the distance between the rollers, which distance can be controlled by means, which will be described hereafter. The cake of the explosive formed in this way is fed by an endless cloth or transmission belt 5, running over said roller 3 and a roller 7 rotatably arranged in frames 6, 19 to the, form rollers 8, 9., which are rotatably arranged-in said frame. As *wi11 be better seen in Figures 2,

6, 8 these rollers are provided with grooves 10, running around their surface, which grooves in both rollers are positioned opposite one another so as to form complete openingsll of suitable form and size. .When

the explosiveis fed from the conveyor 5 to said form rollers which are rotatedby devices suitable for the purpose, the explosive will be formed into a number of parallel strings corresponding to the number of the grooves which strings are received by the endless conveyor cloth or belt 12, running over rotatably arranged rollers 13, 14, and delivered onto another conveyor 15 fogsubsequent treatment, for instance in the case of dynamite, for cutting into suitable lengths of cartridges and packing or embaling in paraflined paper. The plastic explosive is supplied to the working board 1 suitably by means of a receptacle 16, the walls of which are madeup of. a number of frames 17 arranged one above the other, which frames, as

will be seen from the drawings (see Figure upper edge of the topmost frame of the remainingframes (or frame) by means of a wire or other suitable cutting device so that i in such a way a cake of the plastic explosive will be loosened from the mass in the recepta cle which cake then is placed on the board close to the rotating rollers 2, 3 and is caught by the rollers and pressed out as described above when passing between-the rollers to a homogeneous layer or cake of even thickness, which layer, as stated above, by means of the conveyor 5 is delivered to the forming rollers 8, 9.

For driving and adjusting the different members'or parts the following devices are provided. In a frame 19 is a driving shaft 20 rotatably mounted which can be connected to a motor' (not shown) suitable for the purpose. On said shaft two toothed wheels 21, 31 with their bushings are secured. The

shaft 26 is a toothed wheel 27 arrangedin engagement with a' corresponding toothed wheel 28 on the shaft 29 for the upper roller 2. From this it will thus be seen that the engagement of the toothedwheels 27, 28 with each otherwill cause the rollers 2, 3 to rotate synchronously. The forming rollers 8, 9 also are driven synchronously by means of the following devices. On a longitudinal rotatably mounted shaft 30 w-toothed wheel 32 is arranged which gears with-the toothed wheel 31 on the drivin shaft 20 in a similar manner to that describe above with regardto the wheels '21, 22. The shaft 30 can thus be set in rotation by means of the driving shaft 20. On the shaft 30 is arranged a screw wheel 33, which is in engagement with corresponding wheels 34, 35 on one end of the shafts 36, 37 respectively, which carries the forming rollers From this it will thus be seen that the last mentioned rollers onrotation of the shaft 30 will rotate synchronously with each other.

On the last mentioned shaft is also arranged a screw wheel 38 which is in engagement with a wheel 39 arranged on the shaft 40, carrying the roller 13 on which the conveyor belt 14 is running so that this is made to rotate simultaneously with the shafts 8, 9 at a speed corresponding to their peripheral s eed. Bushings 41, in which the shaft pins 3? for the upper forming roller 9 are mounted, are arranged so as to provide a certain pla in vertical direction but are kept norma ly in their lower position, by springs'42 but can beraised against the direction of the pressure of the springs in case any solid object or the like is unintentionally present in the mass to be formed. The toothed wheels 32, 22 are loosely arranged on their shafts 30, 23, but can be coupled in driving connection with said shafts by coupling devices suitable for the purpose, when the couplings are brought into driving position.

According to the form of construction illustrated by way of example in Figure 3, friction couplings are used which are both of similar construction. The Wheel 32 is formed into a sleeve 43. A flanged disc or sleeve 44 corresponding to the inner conical surface of the sleeve 43 is mounted on the shaft 30 in such a way that it may be moved in the axial direction of the shaft but takes part in the rotation of the shaft by means of a projection or the like entering a longitudinal groove 45 in the shaft. By the action of a helical spring 46 arranged on the shaft 30 between the have 47 of the sleeve 44 and a disc 48 fastened to the endof the shaft the sleeve44 is vnormally pressed against the sleeve 43 in such a way that these parts to- As will be seen from the drawings (Fi ure 7 3), a similar coupling device is arrange on the shaft 23 whereby said shaft can be brought into driving connection with the driving shaft 20 by the intermediation of the wheel 22. On the drawings (Figure 3) the coupling members on the shaft '30 are shown in driving connection with each other and the coupling members on the shaft 23 are shown out of connection with each other in which latter case therollers 2, 3 thus do not rotate. By the intermediary of a crank wheel 50, arranged on one end of the shaft 51 one orboth of said couplings can as desired be connected or disconnected. For this purpose the end of the shaft 51 which is mounted in the frame 19 is provided with two cam discs or projections'52, 53 the first mentioned of which is arranged in such a way that upon rotation of the shaft 51 it can be brought to act upon a cylinder 54 mounted on one end, of an angular lever 55, which is pivoted on a shaft pin 56. The other arm 57 of said lever is formed into a U-shaped member or clamp 58 being in connection with a corresponding groove in the nave or hub 47 of the coupling member 44. From this it will thus be seen that by' the turning or rotation of the shaft 51 the lever 55 by1 means of its arm 58 can be brought to move t e coupling member 44 against the effect of tension of the spring 46 to the left (Figure'3) out of connection with the coupling member or sleeve 43, whereby thus the shaft 30 will be disconnected and the rollers driven by said shaft will stop. The shaft 23 can at will be connected or disconnected to the driving shaft 20 by means of an angle lever rotatable around the shaft pin 60 one end of which lever being acted upon by the cam disc 53 in the same manner as described above and the other end of said lever being in connection with the nave 61 of the sleeve 62 in a manner analogous with that described 'sired the thickness of the layer of the ex- Ill , plosive supplied to' the forming rollers the following devices are provided.

The parts 65 of the shaft of the upper roller 2 are eccentrically journalled in .a cylindrical bushing 66, which are again journalled in corresponding frames'4 respectively, 19. By turning the hand-wheel 67, which is arranged on one end of the transversal shaft 68, said bushings 66 can be brought to rotate in such a way that the trunnions 65 can be raised or lowered as desired to some extent depending on the eccentric-a1 mounting.

For this purpose the shaft 68 (see Figure 7) is provided with screw wheels 69, gearing with corresponding driving Wheel 70, mounted on a vertical rotatable shaft 71, which furthermore is provided with a screw wheel 72, in engagement, with a corresponding wheel 7 3, which is connected to the bushing 66.- Upon turning the hand-wheel 67 and the shaft 68 respectively in either direction the bushing 66 will rotate in its bearing which will have for consequence that the trunnion 65 of the roller 2 ecceutrically mounted in the bushing will be raised or lowered. By the use of a screw or helical wheel for the gearing the adjustment of the bushing 65, 66 is automatically secured. so that the bushing cannot rotate by the effect of pressure on the roller 2 but only by rotation of the wheel 67. Figure 7 shows said gearing device in a section on line VII-VII in Figure 2. A

similar device is provided also at the other end of the roller, i. e. in the frame 19 although not shown on the drawings.

Generally it is desired that the strings should have a circular cross-section. For this purpose, however, the grooves in the forming rollers should not have'a semi-circular form, i. e. such a form that two opposite grooves together form a complete circular opening, but in order to gain this purpose said grooves must have approximately such a form as shown in Figure 8, namely such that the opening practically forms a quadrate, the corners of which are somewhatrounded and having their diagonals positioned in a radial respectively axial direction of the rollers.

In the forming process here intended the pressure within the string of the plastic material upon passing through the roller openings will namely be such that the plastic mass after having passed the roller openings takes the form of strings of practically circular cross section.

' From theabove will be seen that the plastic material which is fed through the forming rollers is formed to a number of parallel strings, which are received on the conveyor belt 12 rotating at a speed corresponding to the speed of feeding'from the forming rollers. According-to the present invention there is the advantage that the material by means of a forming process is formedinto a num- I ber of parallel strings, fed at the same speed and thus will be of unifornrquality which involves great practical advantages over methgreater safety is gained against risk of explosion in comparison with what has been the "case in hitherto known methods and dc.- VICGS. for the purpose in question.

Without further explanation it can be seen from the drawings (see for instance Figures 3, 4, and that the gearing devices, etc., are enclosed in casings whereby the explosive is prevented from entering into these gearing or transmission devices and thus explosion is obviated.

It is also evident that details of the'construction of apparatus here illustrated by way of example may be modified without departing from the idea underlying the invention. Thus for instance the coupling devices, by means of which the rollers are coupled into or out of driving connection with the driving shaft 20 and thedevices for ad uSting said coupling devices can be carried out in many difl'erent ways. This is the case also with the devices, by means of which the roller 2 is raisedor lowered.

Havingthus described my invention I declare that what I claim is I Lakppar'atus for preparing plastic explosive 'material in string form for use in the manufacture of dynamite cartridges and the l1ke, which comprises a pair of pressing rollers adapted to press a quantity of plastic adapted to form the material into a plurality of continuous strings separated from one another, and means for conveying said formed strings away from said grooved rollers, said apparatus including a drive shaft, and clutch members for releasably connecting said drive shaft to the pressing rollers and the grooved rollers.

2. Apparatus for preparing plastic explosive material in string form for use in the manufacture of dynamite cartridges and the like, which comprises a pair of pressing rollers adapted topress a quantity of plastic material into sheet form, a'pair of cooperat- .inggrooved rollers, means for feeding said material from said pressing rollers to said grooved rollers, said last named rollers being adapted to form the material into a plurality of continuous strings separated from one another, and means for conveying said formed strings away from said grooved rollers, said apparatus including an operating shaft for each pair of rollers, a clutch member for each shaft rotatably mounted each of said lutch mem ers to said drive shaft, a second clutch member foreach operatin shaft, said second named clutch members ein axially movable on said shafts but restraine against rotational movement inde- 1pindent thereof, spring means for urging said st and'second named clutch mem ers into engagement, a control lever, and means connected to said lever and to said second named clutch members for separately, or collectively disengaging said clutch members upon operation of said control lever. v

3. Apparatus for preparing plastic explosive material in string form for use in the manufacture of dynamite cartridges and the like, which comprises a pair of pressing rollers adapted to press aquantity of plastic material into sheet form, a pair of cooperating grooved rollers, means for feeding said material from said pressing rollers to said grooved rollers, said last named rollers being adapted to form the material into a plurality of continuous strings separated from one another, and means for conveying said formed strings away from said grooved rollers. said apparatus including an operating shaft for each pair of rollers, a clutch member for each.

shaft rotatably mounted -thereon, a drive shaft, gearing connecting each of said clutch members to said drive shaft, a second clutch member for each operating shaft, said second named clutch members being axially movable on said shafts but restrained against rotational movement independent thereof, spring means for urging said first and second named clutch members into engagement, a, control lever, cam members on said control lever, and

' arms connected to said second named clutch members and engaging said cam members, whereby said clutch members may be separately or collectively disengaged against the action of said spring means upon operation 7 1 of said control lever.

4. Apparatus for preparing plastic explosive material in string form for use in the manufacture of dynamite cartridges and \the like, which comprises a pair of pressing rollers adapted to press a quantity of plastic material into sheet form, a pair of cooperating grooved rollers, means for feeding said material from said pressing rollers to said grooved rollers, said last named rollers being adapted to ,form the material into a plurality of continuous strings separated from one another, and means for conveying said formed strings away from said grooved rollers, said apparatus including a rotatable eccentric bearing for one of the pressing rollers, a control shaft, and gearing connecting said shaft and said bearing, whereby said so mounted pressing roller may be raised or lowered upon rotation of said shaft.

In testimony whereof I aflix my signature.

ANTON ERIK ANDELIN.

thereon,- a driveshaft, earing connecting 

